A method of producing products from a fruit mass is generally known in the art. The fruit mass is treated in batches, meaning discontinuously. The fruit mass is poured out on a support in the form of metal sheets, and the water content is reduced by drying to attain a leathery condition of the fruit mass. Usually, drying takes place over several days in ovens through which warm air flows. In this way, one attains a leathery fruit mass which is then cut into separate products. The shape of pieces or strips is realized by longitudinal cutting and transverse cutting. These products are also called “fruit leather”.
An apparatus for drying fruit pulp and similar products is known from German Patent No. DE 36 88 940 T2 corresponding to U.S. Pat. No. 4,631,837. The fruit pulp is processed to attain a leathery condition. Drying is realized similar to a water bath by putting a thin film-like carrier material, especially an elongated strip of Mylar film, on a very long water channel, and by putting the fruit mass on the carrier material. The water is heated close to the boiling temperature such that the essential heat transfer to the fruit mass is realized by the carrier material. The drying operation takes about 2½ hours until the desired consistence of the leathery fruit mass has been reached.
A method of producing confectioneries including a substantial portion of sugar and other similar materials is known from PCT Application published as WO 2006/016897 A1 corresponding to US Patent Application No. US 2008/0199571 A1. Saccharides are used with a share of between 30% and 80%. Furthermore, thickening agents and water are added during production. It is also possible to use fruit masses as a component to influence the taste of the final product. The method is realized in batches, meaning discontinuously, by cooking the ingredients in a closed container for a long time and by stirring the mass such that one attains a mass having a share of dry substance between approximately 85% and 92%. The batch contained in the container is cooked and stirred for a comparatively long time between 15 minutes and 60 minutes. The container is designed to be closed to prevent water and steam from exiting. In certain applications, the container may also be opened for a certain period of time such that it is connected to atmospheric pressure. In this way, products always including a substantial portion of sugar are produced. The sugar has a substantial influence on the texture and structure of the final products. The products include thickening agents, for example pectin. The mass produced in batches is fed from a boiler by a pump, and it is formed to attain the single products using roller forming elements and longitudinal cutting elements and transverse cutting elements.
A method of producing products from fruit is known from U.S. Pat. No. 2,301,589. The fruit, for example apples, are initially washed and then fed to a tray for fruit sorting. The apples are then introduced into an open cooking apparatus from above such that they are cooked under the influence of atmospheric pressure. The mass resulting therefrom is then further processed by a pulper to attain a pulp. A cooking apparatus is located downstream of the pulper, the cooking apparatus operating under the influence of vacuum and sucking in the pulp in this way. The pulper itself operates under the influence of atmospheric pressure. The non-eatable components of the mass are discharged at that place. The mass is transported from the cooking apparatus into a tub and onto a heated carrier strip via a funnel. The mass is further dried on the carrier strip. The entire drying process for attaining the desired share of dry substance of the fruit mass is attained in a method including a plurality of steps and consequently taking a comparatively long period of time.
A method and an apparatus for continuously producing confectioneries from an aqueous solution of ingredients are known from European Patent Application No. EP 1 566 105 A2 corresponding to US Patent Application No. US 2005/0181115 A1. For example, the ingredients may be sugar, sweeteners, liquid glucose and the like. The ingredients are pumped through a helix cooker by a pump. Afterwards, they reach an evaporating chamber in which a vapor valve serves to discharge the vapors. A vacuum chamber is located downstream of the evaporating chamber, the vacuum chamber being separated from the evaporating chamber by a needle valve and being separated from the atmosphere by a discharging unit. The vacuum chamber and/or the evaporating chamber being under the influence of pressure below atmospheric pressure are used for introducing powdery and/or crystalline ingredients. The source of negative pressure is designed and operated to be slightly oversized such that the required vacuum in the vacuum chamber is maintained although there is an open connection to the surroundings. The apparatus is not suitable for producing products from a fruit mass.
A method of producing concentrated fruit juices is described in the German handbook of food chemistry “Handbuch der Lebensmittelchemie, V/2, Obst, Gemüse, Kartoffeln, Pilze”; 1968, SPRINGER, BERLIN, XP008094691, pages 192-195. The fruit juices are evaporated by different types of evaporators which may also be used in combination. The handbook describes long tube evaporators, thin layer evaporators, circuit evaporators, plate evaporators and centrifugal evaporators. In case such evaporators include great evaporating surfaces, they make it possible to reduce the evaporating temperatures and/or the residing times of the juices. Thin layer evaporators operate with extremely low liquid volumes and residing times about 30 seconds, but at a very high temperature difference between the heating medium and the goods to be evaporated. Fruit juices which are evaporated for producing juice concentrates substantially differ from leathery fruit. Fruit juice concentrates serve to be later filled up with water to attain a fruit juice, while this is never realized with leathery fruit.
A method of packaging food is known from U.S. Pat. No. 3,955,003. For example, a leaf made of caramel is produced, and an apple is then wrapped up in the leaf. For producing the caramel, meaning a confectionery, a thin layer vacuum evaporator is used for increasing the share of the dry substance of the confectionery mass to approximately 85%.
A method and an apparatus for continuously producing confectioneries in the form of hard candy including sugar or sweeteners are known from German Patent Application No. DE 40 19 916 A1 corresponding to PCT Application published under WO 92/00016 A1 and European Patent No. EP 0 534 994 B1. The solved sugar or sweeteners are heated in a flow heater until they reach the boiling temperature. They are transported into an evaporating chamber at atmospheric pressure and then into a vacuum chamber being under the influence of vacuum for further evaporation. Such an apparatus is not suitable for producing fruit leather.
A method of introducing fruit juices in a hard candy mass is known from U.S. Pat. No. 5,554,410. A vacuum cooking apparatus is used for cooking. A chamber being under the influence of atmospheric pressure is located downstream. A vacuum chamber is located downstream of this chamber.